Radio antenna



D. JACKSON RADIO ANTENNA May 24, 1949.

2 Sheets-Sheet 1 Filed Nov. 15, 1946 mina Inventor -0ona./o/ Jackson Attorney RADIO ANTENNA Filed Nov. 15, 1946 3O--o I D. JACKSON 2 Sheets-Sheet 2 Inventor flgra/o/ Jclson MM l;

Attorney Patented May 24, 1949 M 2,471,215

UNITED STATES RADIO ANTENNA Donald Jackson, Cambridge, England, a signor to Pye Limited, Cambridge, England, a company of Great Britain Application November 15, 1946, Serial No. 710,118

In Great Britain September 27, 1945 8 Claims. (Cl. 250-33155) ATENT OFFICE 1 2 This invention relates to radio antennae, and Fig. 8 is a fragmentary perspective view showmore particularly to antennae for the reception ing more clearly a detail in the assembly of the of ultra-short waves, such as television signals. structure of Fig. 7.

Among the objects of this invention are to pro- In the preferred form of the invention, the

vide an eflicient ultra-short wave antenna; an antenna structure comprises two rods of suitantenna of simple and sturdy construction which able conducting material, conveniently metal, is simple to erect in a desired location; an anwhich constitute respectively the receiving antenna comprising light but sturdy and durable tenna proper and the reflector, each rod being parts convenient for packing and transportation supported by two stay rods from a housing which but easily assembled into a sturdy and durable o accommodates impedance matching means for structure; an antenna structure incorporating coupling the antenna tothe down lead or cable improved impedance matching means for leading from the structure for connection to a coupling the antenna to the down lead or cable receiver. Preferably, the stay rods not only serve leading from the antenna for connection to a as supports for the antenna and reflector rods, receiver; and an improved impedance matching but are also utilised as feeders for those rods, and

unit for ultra-short wave antennae. Other obare accordingly secured to the antenna and rejects will be in part apparent and in part pointed flector rods at the correct feed points thereof. out hereinafter. The impedance matching means are preferably The invention accordingly consists in the feaconstructed as a unit, preferably by embedding tures of construction, combinations of elements, and enclosing the components thereof in insulatand arrangements of parts as will be exemplified ing material moulded therearound to seal the in the structure to be hereinafter described and components in the moulding, so making the unit the scope of the application of which will be inwaterproof. The matching unit is preferably dicated in the appended claims. provided with terminal connectors over which In this specification and the accompanying 2 the ends of the stay rods entering the housing drawings, I have shown and described a preferred may be fitted, means being provided for holding embodiment of the invention, but it is to be unthose ends of the stay rods captive in the housderstood that this is not intended to be regarded ing. as exhaustive nor limiting of the invention but, Referring now to the drawings, the antenna on the contrary, is given for purposes of illustrastructure shown comprises receiving antenna tion in order that others skilled in the art may and reflector rods 10 and H each fitted with two fully understand the invention and the principles rubber sleeves 32 and each supported by a pair thereof and the manner of applying it in practiof stay rods l2 from the housing I3. For strength cal use so that they may modify and adapt it in and lightness, all the rods are preferably tubuvarious forms, each as may be best suited to the 5 lar and may be made, for example, of aluminium.

conditions ofaparticular use. The antenna shown is intended to be mounted In the drawings, with the rods I0 and II vertical for receiving cer- Fig. 1 is a fragmentary front elevation of the tain broadcast television signals, and the receivantenna. ing rod has been made approximately 10 long Fig. 2 is a partially sectional plan view of part and the reflector rod approximately 11'3" long. of the structure shown in Fig. 1. In view of the lengthof these rods, they may, if Fig. 3 is a fragmentary elevation showing more desired, each be made in two or -more sections clearly a detail of the structure of Fig. 1. adapted to be joined together end to end, for

Fig. 4 is a fragmentary side elevation showing example, by making each rod section of halfthe housing and bracket assembly. round cross-section at the joint and bolting the Fig. 5 is afragmentary partially sectional front joints together. For such an antenna, the stay elevation of the assembly of Fig. 4, with one half rods l2 may each be approximately 2'6" long, of the housing and of the bracket removed. and each being connected at its outer end to the Fig. 6 is a fragmentary exploded sectional view associated vertical rod at the correct point for of the housing with a stay rod in position, the utilising the stay rod as a feeder. With the rod section being taken along the line -B6 of Fig. 5 dimensions given, the outer ends of the stay rods but with the other half of the housing shown in have been secured to the vertical rods at a disexploded position. tance approximately 1'3" from the midpoint of Fig. 7 is an elevation of the impedance matcheach vertical rod. For effecting a firm and seing assembly prior to being moulded, and cure connection, the outerends I4 of the stay rods l2 are bent at an appropriate angle and squashed into a concave form to snugly embrace the vertical rods (as better seen in Figs. 2 and 3), and are fitted correspondingly shaped clamping shoes l5, bolts It being passed through registering holes in the vertical rods, outer ends of the stay rods and the clamping shoes to bolt' the rods together. The bolts H5- may benu'tted; as shown, or the holes provided in the clamping shoes l5 may be extruded and tapped, into which the bolts are screwed.

The stay rods 12 are arranged at inclinations to the vertical rods so thattlfe innerendsof the stay rods enter the housing 3 radially. The housing I3 is preferably made of insulating material, conveniently a plastic moulding, and is'made in two similar matching halves l3w,, l'3b formed with radial matching grooves one of which is seen at I! in Fig. 6, for accommodating the inner ends of the four stay rods. The inner end of each stay rod is provided with a pair 05 diametrically opposed holes throng-h which a pin I-'8- isinserted and the ends of which extend into blind holes, one of which is seen at 9 in Fig io, formed in the housing halves at thebott'o'msof the grooves ll so as to locate and hold the stay rods captive in the housing l3; The latter i's' fo'rme'd with a hollow centre portion whichaccommodates a moulded impedance matching unit 20 having metallic terminal caps 2 L disposed at the correct angles for insertion respectively into the inner ends of each of the four tubular stay rods, asmore clearly shown in Fig. 5.

The housing halves Md; I36 are also formed with matching grooves (-notclearly seen in the drawings) through which ascreened coaxial cable 22 from the matching unit 20 passes out of the housing l3, along with afl'eitible' grounding conductor 23 from. the unit.

In assembling the" housing t3; the four stay rods [2 may be pressed on to the caps 21' of the matching unit 20', and the unit laid in the centre of one of the housing halves, say I36, as shown in Fig; 5, with the inner ends of the stay rods resting in their grooves Hand the cable 22 and grounding wire 23 laid in: their groove, as shown, the arrangement being such that the locating pins [8 can be inserted in position. The other housing half is then laid on top, and the two housing halves t3'a, I 35 bolted by nutted bolts 24 passed through holes ill (Fig. 5') in the housing halves, to hold all the parts in the correct assembled relation.

As shown, certain of the bolts 24 are" also utilised for clamping to the housing l--3-' a bracket 25' for mounting the structure ona suitable support, here shown as a tubular metal pole 26 The bracket 25 is in two similar'halves 25a, 251), each comprising a flanged part-cylindrical portion 2'! for embracing the top end ofthe supporting pole 26 and a flanged tapered plate portion- 28' for attachment to the housing. The flanges of the two bracket halves have holes therein, those in the flanges of the plate portions 28' receiving certain of the bolts 24, and the holes 30 (Fig. 5) in the flanges of the part-cylindrical portions- 21 receiving nutted bolts 31 for clamping the bracket around the top of the pole.

It will be noted that there are some of the bolts 24 which are not required for assembling the bracket halves 25a, 25b on the housing [3. This provision facilitates the assembly operations by enabling the housing [3, matching unit 20 and stay rods l2 to be as embled and securely bolted up by those bolts before proceeding to assemble the bracket 25 with the aid of the remainder of the bolts 24. After bolting the bracket halves to the housing l3 and before inserting the pole 26 into the socket formed by the bracket portions 2?, the cable 22 is passed through the pole, which may conveniently be done by weighting the end of the cable and dropping it down the pole, whereafter the top end of the pole is inserted into the bracket portions 27 which are then tightened about the pole by the bolts 3|. The grounding conductor 23 protruding from the housing i3 is nutted to one of the bracket bolts 3!, as shown. A suitable apertured plug 32, for example of wood, may be slipped over the end of the cable and pressed into the bottom end of the pole 26 in order to prevent the cable from chafing against the bottom edge of the pole. The assembled antenna may then be erected in the desired location by hoisting and clamping the pole to a wall or chimney structure, for example.

For the described antenna having a receiving rod and a reflector rod, the impedance matching unit 23 incorporates a matching transformer for the receiving rod and a balancing coil for the reflector. A preferred construction is shown in Fig. 7, this figure showing the assembly of components prior to being embedded in an insulating moulding. Two cylindrical formers 33 and 34 of insulating material are located in substantially parallel spaced relation by two substantially parallel spaced metal strips 35 and 36 which support the formers. Each former carries at its ends two of the connector caps 2| of the unit, each cap being secured to its former by a tag 31 arranged at an inclination to the cap axis so that the cap is disposed in the correct angulardirection for receiving the end of the associated stray rod l2 earlier mentioned. Each cap 2| and its tag 3: may be stamped and formed in one piece from strip metal. The ends of the supporting strips 35, 3B and the tags 37 are all secured to their formers in identical fashion, which may be more clearly understood from a consideration of Fig. 8 in conjunction with Fig. 7.. Fig. 8 is illustrative of the mode of attachment at either end of either former. The end of each tag 31 and each end of each of the strips 35,36 is formed with a radiused edge 38 from which projects a narrow tongue 39 which is passed through a pair of aligned diametrically opposed slots 40 in the former, so that the radiused edge snugly abuts against and partially embraces the circumference of the former (as clearly seen in Fig. 7) and a portion M at the extremity of the tongue protrudes through the former. The portion 4| is then twisted out of alignment with the main body of the tongue and with the adjacent slot Ml, thereby securing the strip 35 or 36 or tag 3-1, as the case may be, to the former. To facilitate such twisting, the tongue 39 is reduced in width at 42, immediately behind its extremity portion 4!.

On one former 34 is wound the matching transformer denoted generally by 43. First applied is the secondary which may consist of copper foil strip wound with interleaved insulating strip, the copper being next to the former. The copper strip may have its ends of reduced width and bent at right angles to the main body of the strip and winding so as to provide tags 44, which are respectively connected by soldering to the two metal supporting strips 35, 36. On this secondary winding is wound the primary winding which may consist of a number of double turns of enamelled copper wire, one end 46, 41 of each of the two coils of wire serving as the ends of the primary winding and being connected by soldering respectively to the tags 37 of the two connector caps 2| mounted on the former 34, and the other ends 48 of the two coils being twisted or otherwise connected together to form a centre tap for the primary windin which is connected by soldering to the lower supporting strip 35.

On the other former 33 is wound the balancing coil 49 for the reflector, consisting, for example, of a number of turns of enamelled copper wire. The ends 58, 51 of the coil d9 are respectively connected by soldering to the tags 3'! of the two connector caps 2| mounted on the former 33.

The end of the screened coaxial cable 22 to be connected to the matching unit has its sheathing metal braid (constituting its outer conductor) stripped back, and the lower supporting strip 35 is provided with a hole therein through which the stripped end portion 52 of the cable is passed, the upper supporting strip 3%; also having a hole therein through which the centre conductor 53 of the cable is passed and connected by soldering to the upper supporting strip 35. The outer conductor braid 54 of the cable is connected by soldering to the lower supporting strip 36. grounding conductor 23, which may be a length of tinned copper braid provided with a terminal tag 55 at one end is also connected by soldering to the lower supporting strip 36.

The impedance matching assembly described and shown in Fig. 7 is then placed in a die and a suitable insulating materiaLsuch as polythene plastic, moulded therearound to form the moulded unit 26 having the matching assembly embedded therein, with the connector caps 2! exposed and positioned for insertion in the ends of the. stay rods 12.

For some purposes, the reflector rod may not be necessary and may be omitted, in which case the antenna may comprise the aerial rod and its associated stay and feeder rods, together with the housing and the impedance matching unit, which need not in that case incorporate a balancing coil. Further, for the reception of some signals, the rods which have herein been called vertical rods would have to be disposed in a horizontal or some other non-vertical position.

I claim:

1. An ultra-short wave antenna comprising an antenna rod, a reflector rod spaced from said antenna rod, a housing between said antenna and reflector rods, a coaxial cable having one end thereof within said housing and extending from said housing, impedance matching means Within said housing for coupling said antenna rod to said cable, said matching means being conductively connected to said end of said cable, means for supporting said housing, a pair of metallic stay rods supporting said antenna rod from said housing, said stay rods being conductively secured at one end thereof to said antenna rod at spaced iced points therealong and the other ends of said stay rods extending into and being secured within said housing in conductive connection with said matching means for the purpose and with the efiect that said stay rods function also as feeders connecting said spaced points of said antenna rod to its said matching means, impedance matching means within said housing for said reflector rod, a second pair of metallic stay rods supporting said reflector rod from said housing, said second pair of stay rods bein conductively secured at one end thereof to said reflector rod at spaced feed points therea-long and the other ends of said second pair of stay rods extending into and being The of said cable within said housing, an impedance matching unit within said housing including an insulating moulding having exposed terminal connectors thereon and impedance matching means for coupling said antenna rod to said cable embedded and sealed within said moulding and conductively connected to said terminal connectors, said end of said cable being embedded and sealed in said moulding in conductive connection with said matching means, means for supporting said housing, a pair of metallic stay rods supporting said antenna rod from said housing, said stay rods being conductively secured at one end thereof to said antenna red at spaced feed points thereaiong and said stay rods extending at the other ends thereof into said housing, said other ends of said stay rods being tubular and respectively 'tting over said terminal connectors of said matching unit to conductively connect said stay rods with said matching means for the purpose and with the effect that said stay rods function also as feeders connecting said feed points of said antenna rod to its said matching means, and means for holding said tubular ends of said stay rods captive in said housing.

3. An antenna as defined in claim 2, said housing comprising two recessed matching halves forming a chamber to accommodate said impedance matching unit and having matching grooves forming apertures through which said stay rods respectively enter said housing, cross pins respectively passing transversely through said tubular ends of said stay rods and having the extremities of said pins received in recesses in said housing halves to locate and hold said stay rods captive in said housing, and means for securing said housing halves together.

4. An antenna as definedin claim 3, and fur-. ther comprising a pair of bracket members posi- 'tioned at opposite sides of said housing, means for securing said members together to clamp said housing between them, said members having matching portions extending beyond said housing and forming a socket for receiving a supporting pole :for the antenna.

5. An ultra-short wave antenna comprising an antenna rod, 9, reflector rod spaced from said antenna rod, an insulating housing between said antenna and reflector rods, a coaxial cable extending from said housing with one end of said cable within said housing, an impedance matching unit within said housing including an insulating moulding having two pairs of exposed terminal connectors thereon, impedance matching means for coupling said antenna rod to said cable embedded and sealed within said moulding and conductively connected to a first pair of said terminal connectors, and impedance matching means for said reflector rod embedded and sealed within said moulding and conductively connected to the second pair of said connectors, said end of said cable being embedded and sealed in said moulding in conductive connection with said matching means for said antenna rod, means for supporting said housing, a first pair of metallic stay rods supporting said antenna rod from said housing,

saidc'zstayrods ibeing conductively, secured at one endtithereofito. said antenna 1 rod. at spaced feed.

points; therealong; and said stay rods extending at'ztheqotherendsthereof'into said housing, said other endstof said stay'rods being tubular and respectivelyfittingover said first pair ofterminal connectors .to conductively connect said first pair ofzstayrods with said matchingmeans for said antenna-rod; whereby said stay rods function also assfeeders connecting the said feed points of said antenna rod to its said matching means, a second ipairioi metallic stay rods supporting said refiector. rodf-from' said housing, said second. pair of .stay rods being conductively secured at one. ends-thereof to said reflector rod at spaced feed ppintsztherealong and extending at the other ends thereof into said housing, said other ends of said.

secondwpairof stay rods being tubular andrespectively fitting over said second pair of terminal connectors to' conductively connect said second pain. of stayrods with said matching means for sa-idwreflector rod, whereby said second pair of stayrods'function also as feeders connecting the saidifeed'zpoints of said reflector rod to its saidmatching means, and means for holding said tubular ends of all. said stay rods captive .in said housing.

6. An antenna as defined in claim 5,- saidhousingycomprisingtwo recessed matching; halves forming a chamber to accommodate said im-- pedance matching unit and having matching.

groovea forming apertures through whichsaid stay; rods respectivelyenter saidhousing, cross pins respectively passing, transversely through said'tubular endsof said staytrodsand having the extremities of said .pins'; received" in' recesses in: saidi housing halvessto-zlocate and hold said' stay; rods acaptive. inisaid housing; and: means "for-se flectorsrodaca coaxialcableextending from said housing with one end thereof .within said housing,

two-pairs:oteinetallicstay rodsflradiating from said housing ancLhavingJnnertubular ends secured. within. said-housing, the outerends of afirst pair. of saidistay, rods. beingconductively attached to said antennarodatspaced feed points therealong. substantially. equidistant from the midpointoflsaidantennarod, theouterends of the secondpair:of-fsaidstay rods being conductively attachedto said reflector rod at spaced feed points therealongsubstantially equidistant from the midpoint ofsaidreflector rod,.,an impedance matching unit-within said housing including an insulating moulding having .said. end of said cable em.- bedded -and sealed therein and having two pairs of Q terminal connectors.v radiating therefrom respectively, aligned with and fitting within said tubular. inner ends" of said stay, rods sothat afirst pairof 'saidi'connectors is. conductively connected respectively to said first pair ofstay rods and the secondlpain of.v said. connectors is conductively connected respectively-to saidsecond pair of stay rods, an. impedance matching transformer for couplingsaidantenna rodito said cable embedded and'sealed'iwithin saidimoulding and having a primary winding conductively connected to said firstpair oficonnectors and having a secondary winding connected; to the. conductors of said cable, said .matchingum't. also including an imnedance\balancing,;.coil'forsaid reflector rod em.- bedded andtsealed'withinsaid moulding and con-. ductively"'connectedflto said second pair of connectors; whereby said pairs of stay rods respectivelygfunctional'so as'feeders connectingsaid feed points off'said antenna rod to said transformer and saidfed points"of"saidreflector rod to said balancing coil.

DONALD J ACKSON.

REFERENCES CITED Thefollowing: references are of record in the file of this patent:

UNITED STATES PATENTS Number? Name Date 2,251,997 Goldmann' Aug. 12, 1941 2,255,520 Schuster Sept .9, 1941 2,349,976: Matsudaira. May 20, 1944 2,380,333? Scheldorf" July 10, 1945 

